Lowering a high red blood cell count typically involves a combination of medical procedures, medication, and lifestyle changes, depending on what’s causing the elevation. For most people with a clinically high count, the fastest and most direct method is therapeutic phlebotomy, which is essentially a controlled blood draw that reduces the volume of red cells circulating in your body. The target is usually a hematocrit (the percentage of your blood made up of red cells) below 45%.
Why a High Red Blood Cell Count Matters
When your body produces too many red blood cells, your blood becomes thicker and moves more slowly through your vessels. This raises the risk of blood clots, stroke, and heart attack. In a large study of patients with polycythemia vera (the most common disease-related cause of high red cell counts), about 28% experienced a blood clot during follow-up, and ischemic stroke accounted for 46% of those events. Patients who developed clots had dramatically higher mortality compared to those who didn’t.
A high red blood cell count doesn’t always mean you have a blood disorder. Smoking, living at high altitude, dehydration, and certain medications can all push your numbers up. The approach to lowering your count depends entirely on the cause.
Therapeutic Phlebotomy
Phlebotomy is the first-line treatment for most people with dangerously elevated red blood cell counts. It works exactly the way it sounds: a healthcare provider removes a measured volume of blood, typically 200 to 800 mL per session, not exceeding about 13% of your total blood volume. Think of it as donating blood on a schedule designed to bring your levels down.
During the initial phase, sessions may happen every day or every other day until your hematocrit drops to the 40 to 45% range. Research from the Korean Journal of Blood Transfusion found that intervals shorter than two weeks were most effective at reducing hematocrit, while intervals under four weeks worked best for maintaining it once normalized. After you reach your target, you’ll typically need blood counts checked every four to eight weeks, with occasional maintenance phlebotomies as needed.
The procedure itself is straightforward and usually takes 15 to 30 minutes. You may feel lightheaded or fatigued afterward, which is normal. Staying well-hydrated before and after each session helps.
Medications That Reduce Red Cell Production
When phlebotomy alone isn’t enough, or when you need treatment frequently, your doctor may add medication to slow your bone marrow’s production of red blood cells. This is more common in people over 60 or those who’ve already had a blood clot.
The most widely used medication works by directly suppressing the bone marrow’s ability to make new blood cells. For people who don’t respond well to that approach, a second option targets specific signaling proteins (called JAK1 and JAK2) that drive overproduction. In real-world data, most patients starting this second medication begin at 10 mg twice daily.
A newer class of treatment mimics hepcidin, a hormone that controls iron availability in your body. By limiting the iron supply your bone marrow needs to build red blood cells, these drugs can dramatically reduce the need for phlebotomy. In a phase 2 clinical trial, patients who previously needed an average of about 9 phlebotomies per year dropped to fewer than 1 per year while on the medication, with consistent hematocrit control over long-term follow-up.
Aspirin for Clot Prevention
Low-dose aspirin (100 mg daily) is a standard recommendation for people with high red blood cell counts caused by polycythemia vera. It doesn’t lower your red cell count directly, but it reduces the stickiness of platelets and helps prevent the clots that make the condition dangerous. Some evidence suggests that people at particularly high cardiovascular risk may benefit from taking that dose twice daily rather than once, since the antiplatelet effect may wear off before 24 hours in this population.
Lifestyle Changes That Help
Quit Smoking
Smoking is one of the most common reversible causes of elevated red blood cell counts. Carbon monoxide from cigarette smoke reduces the oxygen-carrying efficiency of your blood, and your body compensates by producing more red blood cells. After quitting, most blood cell parameters return to levels similar to those of people who never smoked within two years. Some markers, particularly certain white blood cell counts, take two to five years to fully normalize. The red blood cell improvements tend to come in the earlier part of that window.
Move to a Lower Altitude
Living above about 5,000 feet triggers your body to make more red blood cells to compensate for thinner air. If you relocate to a lower elevation, your body gradually dials back production. Research published in Blood found that red cell production drops significantly within two to five weeks of descending to sea level, with total blood volume changes taking several additional weeks to stabilize. This is a natural correction that doesn’t require any medical intervention.
Stay Hydrated
Dehydration concentrates your blood, making your red blood cell percentage appear higher than it truly is. This is sometimes called “relative polycythemia” because the cell count isn’t actually elevated, there’s just less plasma diluting it. Drinking adequate water throughout the day can normalize a mildly elevated hematocrit in these cases. If your levels drop to normal with proper hydration, the elevation was likely a fluid issue rather than a production issue.
Dietary Considerations
About two-thirds of your body’s iron goes directly into hemoglobin, the protein inside red blood cells. Without enough iron, your bone marrow simply can’t build red cells at its usual rate. This is why people who undergo frequent phlebotomy often develop low iron stores over time, which actually helps keep red cell production in check between sessions.
Some doctors advise patients with polycythemia vera to avoid iron supplements and limit iron-rich foods like red meat and fortified cereals, though formal clinical guidelines stop short of recommending a strict low-iron diet. The goal isn’t to make yourself iron-deficient, which causes its own problems like fatigue and weakness. It’s to avoid feeding the overproduction. This is a conversation to have with whoever is managing your blood counts, since the right approach depends on your specific iron levels and how frequently you’re getting phlebotomy.
What Counts as “Too High”
The World Health Organization’s diagnostic criteria for polycythemia vera set the hemoglobin threshold at above 16.5 g/dL for women and above 18.5 g/dL for men. Hematocrit values above 56% in women or 60% in men are also flagged. But your doctor may be concerned at levels below these cutoffs, especially if your numbers have been climbing over time or you have other risk factors for clotting.
A single elevated reading doesn’t necessarily mean you need treatment. Dehydration, a recent intense workout, or the timing of your blood draw can all influence results. Persistent elevation across multiple tests is what typically triggers further evaluation, including genetic testing for mutations associated with polycythemia vera.